Pneumatic action for player-pianos and similar musical instruments.



' UNITED STATES rA-rnn'r osnion."

GUSTVE BJORKLAND, 0F BAYONNE, NEW' JERSEYL PNEUMATIC ACTION FOR PLAYERPIANOS AND SIMILAR MUSIGAL INSTRUMENTS.

To all whom 'it may concern Be it known that I, GUSTAVE BJORKLAND, a citizen of the United States7 residing at Bayonne, county of Hudson, and State o1n4 New Jersey, have invented a new and Iniproved Pneumatic Action for Player-Pianos and Similar Musical Instruments, of which the followingl is a specification.

The invention relates to a pneumatic action of novel construction in which a single valve is employed in lieu of the primary and secondary valves hitherto enerally used. This desirable change is e ected without diminishing the repeating quality of the in strnment or causing an undesirable loss of vacuum.; In this Way, the construction is simplified, valuable space econolnized and the cost of the action considerably reduced.

The invention consists more particularly in providing in addition to the conventirmal bleed hole an air vent which is controlled by the diaphragm and which is adapted to establish ample supplementary communication between the vacuum chamber and the air space on the opposite side of the dia* phragm. In this Way the air is rapidly exhausted from said air space Whenthe tracker bar opening is closed7 so that quick repeti! tion of the same note may be obtained.

The invention further comprises various novel features of construction, all as more fully pointed vont in the appended claims.

In the aecomlmnying drawing: Figure l. is a cross section of a valve chest embodying my invention on line 1--1, Fig. Fig. la a similar section partly broken away, showing the parts in a different position; Fig. 2 a

`sectional plan view, partly broken away, ot

the valve chest; Fig. 3 a modification ofthe bleeding means; Fig. l a rear view of thediaphragm seat shown in Fig, l, and Fig. v5 a rear view ot' the diaphragm seat shown in Fig. 3.

The valve chest l() is provided with a lon gitudinal vacuum duct Il from which 'the air is permanently withdrawn through pipe l2 in the usual manner. Chestl() is shown to be mounted on a rail 13 to the lower face oiE which the pneunnities or elbows lll are Secure-d. The movable boards 15 ot the lat ter are provided with arms 16 that engage the litters olf the piano hammers (not shown) as usual. Each bellows la con'nnw nicates through passage- 17 with a valve chamber 18 formed in chest l0 und adapted to be brought into communication with duct Specification of Letters Fatemi.

Application filed September 14, 9l.

Patented Apr. '23, 191.2.

Serial Nc. *S-9,221.

20, said ports being respectively controlled by dislc valves 2l, 22 ich are adjustahly mounted on a commen stein 28. Each port 2G is preferably i''ormedin separate cap 24e remo ably secured to bor` l0 by screvv's' and provided with a hushed bearing 2G for stem By thus employing a separat-l cap tor each valve, the latter may be readily removed for adjustment, ete., without necessitating a dismantling of the valve action, as has heretofore been generally imperativec At its rear end each stein 23 provided* with an adjustable shoe 2'? 'which is guided in a perforated hushed rail 28 mounted with in duet ll. 2'? bears against a cushioned plate 2) secured to the center of' a pouch or diaphragm 30., Vllhe latter is preferably interposed between a pair of plates 3l, which are in turn secured to box l@ by screws B3, the plate lil being provided with a circinar openingI 2li. aecoini'nodatina4 shoe 2l'. Baeli'o'f diaphragm 2li), there is formed in plate 32 a recess which is by port connected. e passage rEhe latter communieates through flexible tube il? with the corresponding opening of the tracker bar {not shown). In alineinent with passage 36, clamped section ol d'aphrag'in 30 is perforated :is at to establ i connnunieation between said passage and a chamber 39 formed in plate Si, Vwhile a bleed hole permanently connects said eli-amber with duct il. As clearly illustrated :i Figs. 'l and Q, the dian'ieter of opening 3T considerably smallerthan thatl ot recess while the preferably circular chamber in close proximity to opening Il l paratively thin web il separating said chamber and opening. @wing to this particular construction, chamber 39 willr be partly u overed when the diaphragm is aised oil plate 3l l) to establish coinn'iuniea'tion between chanibc'- 22) and duet ll in addition to that obtai Ll0, 'the partel ll, 3l thus cons phragmfeontrolled vent. plirag'li is drawn against platt it will close chamber 39 aojai that the bleed hole it) exclus said chamber and duct.

il or with the atmosphere through ports 19,

ned by bleed hole Vlvlorinally the valve spindle and dia phragxn occupy the position .illustrated in tracker bar7 duet, air will beI admitted through tube 37, passage 36 and port 35 into recess 34, thus permitting diaphragm 3o in be sucked toward `duct 11 (Fig. 11). In this way stem Q3 will be shifted toward the right to close port 2O and open port 19, thereby collapsing bellows 14 and thus actuating the corresponding piano hammer. When the tracker bar duct is again closed by an imperforate portion of the tune sheet, vacuum will be established through bleed hole 40 behind the diaphragm, and the vacuum within duct 1l will draw 'disk 21 against its seatto admit air into bellows 14: and thereby expand the same. It will be seen thatI after diaphragm 30 has started t0 move from the position shown in Fig. l"l to that shown in F ig. l, it will be raised ot'f plate 3l to establish a comparatively large bleed between chamber 39 and opening 3l, in addition to bleed hole 40. In this way the air is rapidly withdrawn from behind the diaphragm, thus permitting a quick return movement ot' stem 23 and of the valve disks carried thereby.A Although a large bleed area is thus formed between duet ll and passage 36 during the return of the diaphragm, the diminutive bleed hole Lt0 .only is openwhile the tracker bar opening is uncovered, so that the loss of vacuum is minimized.

In Figs. l and 2, the bleed hole is located opposite duct 3G, so that it may be readily cleaned with a needle-like instrument inserted through said duct after tube 37 has been removed. In Fig. 3 the bleed is formed by a groove 42 cut into web 4l. When the diaphragm 30 is drawn against its seat on plate 31, groove l2 only establishes communication between duct 1l and passage 3G, while upninthen'i'tlidrawal of the diaphragm from said seat, die desired large bleed is obtained.

From the foregoing, it is evident that with my novel single valve player action, the same result is obtained as has hereto tore been possible only with a double or primary and secondary valve action, namely a quick withdrawal ot the air Jfrom behind the' diaphragm, to permit rapid repetition.

The diaphragm ot my single valve 1n swinging back and forth, will alternately open and close the air vent that supplements the exceedingly small bleed hole proper, thereby preventing any loss of vacuum as is the case when, a large bleed is employed. In addition to rendering rapid repetition possible, economy of space isobtained, while the cost of the pneumatic action is considerably reduced.'

I claim:

1. In a pneumatic valve action for player pianos and similar musical instruments, a valve chest having a vacuum duct, an air passage, a bleed permanently connecting said duct and passage, an air vent adapted to establish communication between the duct and passage in addition to the connection formed by the bleed, and a diaphragm controlling said vent. y

2. Ina pneumatic valve action for player pianos and'similar musical instruments, a valve chest having a vacuum duct, an air passage, a bleed permanently connecting said duct and passage, an air vent adapted to establish connnunication between the duct. and passage in addition to the connection formed by the bleed, a hammer actuating bellows, a valve controlling communication between the duct and said bellows, and a diaphragm cooperating with said valve and adapted to directly open and close said vent.

3.' In a pneumatic valve action for player pianos and similar musical instruments, a valve chest having a vacuum duct, a diaphragm seat, a chamber opening into said seat., a diaphragm adapted to engage the scat and thereby separatel the chamber from the duct, and a bleed for establishing permanent communication between the cham ber and duet independent from the diaphmgm-controlled vent.

el. In a pneumatic valve action for player pianos and similarniusical instruments, a valve chest having a vacuum duct, a plate secured to said chest and having an opening and a chamber located in proximity to said opening, a diaphragm adapted to alternately establish and interrupt communication between said opening and chamber, and a bleed 'for establishing pe'nanentcomnunication between the chamber and duct independent from the diaphragm controlled vent.

GUSTAVE BJ'ORKLND. lVitnesses FRANK v. Bmnsnn', .Karnnnvxn Koen. 

